Clearly, there’s reason to worry. Back in 2000, before they almost ruined the economy and had to be bailed out, the five biggest banks on Wall Street held 25 percent of the nation’s banking assets. Now they hold more than 45 percent.

Their huge size fuels further growth because they’ll be bailed out if they get into trouble again.

This hidden federal guarantee against failure is estimated be worth over $80 billion a year to the big banks. In effect, it’s a subsidy from the rest of us to the bankers.

And they’ll almost certainly get into trouble again if nothing dramatic is done to stop them. Consider their behavior since they were bailed out.

In 2012 JPMorgan Chase, the largest bank on Street, lost $6.2 billion betting on credit default swaps tied to corporate debt – and then publicly lied about the losses. It later came out that the bank paid illegal bribes to get the business in the first place.

Last May the Justice Department announced a settlement of the biggest criminal price-fixing conspiracy in modern history, in which the biggest banks manipulated the $5.3 trillion-a-day currency market in a “brazen display of collusion,” according toAttorney General Loretta Lynch.

Wall Street is on the road to another crisis.

This would take a huge toll. Although the banks have repaid the billions we lent them in 2008, many Americans are still living with the collateral damage from what occurred – lost jobs, savings, and homes.

But rather than prevent this by breaking up the big banks and resurrecting Glass-Steagall, Hillary Clinton is taking a more cautious approach.

She wants to impose extra fees on the banks, with the amounts turning not on the bank’s size but how much it depends on short-term funding (such as fast-moving capital markets), which is a way of assessing riskiness.

So a giant bank that relies mainly on bank deposits wouldn’t be charged.

Clinton would also give bank regulators more power than they have under the Dodd-Frank Act (passed in the wake of the last banking crisis) to break up any particular bank that they consider too risky.

In addition, a lucrative revolving door connects the Street to Washington. Treasury secretaries and their staffs move nimbly from and to the Street, regardless of who’s in the Oval Office.

Key members of Congress, especially those involved with enacting financial laws or overseeing financial regulators, have fat paychecks waiting for them on Wall Street when they retire.

Which helps explain why no Wall Street executive has been indicted for the fraudulent behavior that led up to the 2008 crash. Or for the criminal price-fixing scheme settled in May. Or for other excesses since then.

And why even the fines imposed on the banks have been only a fraction of the banks’ potential gains.

And also why Dodd-Frank has been watered down into vapidity.

For example, it requires major banks to prepare “living wills” describing how they’d unwind their operations if they get into serious trouble.

But no big bank has come up with one that passes muster. Federal investigators have found them all “unrealistic.”

That’s not surprising because if they were realistic, the banks would effectively lose their hidden “too-big-to-fail” subsidies.

Given all this, Hillary Clinton’s proposals would only invite more dilution and finagle.

The only way to contain the Street’s excesses is with reforms so big, bold, and public they can’t be watered down – busting up the biggest banks and resurrecting Glass-Steagall.

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